Electric storage batteries (e.g., lead-acid, Ni-Zn, etc.) comprise several galvanic cell elements each immersed in an electrolyte and encased in separate compartments of a substantially leak-proof container. Each cell element comprises at least one plate-like, positive electrode (i.e., a positive plate), one plate-like negative electrode (i.e., negative plate) and a porous separator (e.g., a thin microporous sheet and/or absorbent glass mat) therebetween. Multi-plate cell elements are commonplace and comprise a stack of alternating positive and negative polarity plates interleaved one with the other and the separators. The plates themselves each comprise a conductive substrate which supports an electrochemically active material thereon and conducts electrical current substantially uniformly therethrough. In Pb-acid batteries, for example, the plates comprise a leady active material (i.e., PbO.sub.2 for the positive plates and Pb for the negative plates) pasted onto a reticulated Pb-alloy grid substrate. A lug projects from the substrate/grid of each plate and serves to electrically couple the plate to other electrical components (e.g., terminals, other plates, etc.) of the battery. One such coupling occurs between aligned lugs of like polarity plates within a multi-plate cell element and thence, via an intercell connector, to opposite polarity plates in adjacent cells. In some instances, the lugs are coupled by simply bundling and welding the plates lugs together through an aperture in an intercell partition of the container such as shown in FIG. 5 of U.S. Pat. No. 4,046,062to matter. More typically, however, the several plate lugs are electrically coupled one to the other by a bus bar, known as a plate strap, which is burned to, or cast about, the plate lugs: (1) inside the battery container such as disclosed in FIG. 2 of the aforesaid U.S. Pat. No. 4,046,0672; or (2) outside the battery container such, for example, as disclosed in Eberle U.S. Pat. No. 3,841,915 where the plate strap is formed in the container's cover.
It has been proposed to position preformed strips of insulating material over the lugs of each set of aligned positive or negative plate lugs (e.g., see U.S. Pat. No. 2,287,802) to facilitate manufacturing, to rigidify the stack, and/or to prevent accidental internal short circuiting of the cell. Likewise, it has been proposed to fit a preformed trough over the plate lugs to form a mold for forming a cast-in-place plate strap onto the plate lugs and through the intercell partition (e.g., see U.S. Pat. No. 3,988,169). Finally, our own copending U.S. Pat. application Ser. No. 783,359 filed Oct. 3, 1985 entitled "Electric Storage Battery", which is incorporated herein by reference, discloses pressure molding a strip of plastic in and about the roots of aligned plate lugs to tightly engage the lugs and to firmly hold them in precise alignment with, and spaced from, each other. This latter approach to providing a plastic strip on the roots of the lugs requires stocking a variety of different molds in order to accommodate cell elements having different numbers and thicknesses of plates.
There exists a need for an even better way for providing a strip of insulating material about the plate lugs of a cell element. Moreover, there exists a need for a way to provide a leak-tight seal between the plate lug(s) and an external wall of the battery container.
Accordingly, it is an object of the present invention to facilitate battery assembly by providing the lug(s) of each battery plate with its own individual, tight-fitting, insulating collar which mates: with similar collars on other lugs to form a segmented insulating strip at the roots thereof; with similar collars on other lugs to form a mold for forming a plate strap about the plate lugs; and/or with an aperture in a container wall to facilitate the formation of a substantially liquid-tight seal therewith. It is a more specific object of the present invention to provide a galvanic cell element having a segmented strip of insulating material about its plate lugs, which strip comprises a plurality of discrete lug collars in aligned abutting relation one to the other. These and other objects and advantages of the present invention will become more readily apparent from the detailed description thereof which follows.